/Engine/Plugins/Experimental/Mutable/Source/CustomizableObject/Public/MuCO/CustomizableObjectMipDataProvider.h
Return true unless the texture update needs to be aborted because the mip won't be updated correctly (for example IO error).
virtual bool PollMips ( const [FTextureUpdateSyncOptions](API\Runtime\Engine\Streaming\FTextureUpdateSyncOptions) & SyncOptions )